Image processing apparatus

ABSTRACT

An image processing apparatus includes an image pickup circuit having a plurality of photographic modes, such as television standards, a compression processing circuit for performing compression processing of an image pickup signal outputted from the image pickup circuit, the compression circuit having a plurality of compression modes, and a selecting circuit for selecting one of the compression modes of the compression processing circuit in accordance with a selected one of the photographic modes of the image pickup circuit.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of application Ser. No. 10/195,266,filed Jul. 15, 2002 now U.S. Pat. No. 7,024,101, which is a divisionalof application Ser. No. 08/665,766, filed Jun. 19, 1996, now U.S. Pat.No. 6,453,120, which is a divisional of application Ser. No. 08/218,574,filed Mar. 28, 1994, now U.S. Pat. No. 5,563,661, the entire disclosuresof which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an image processing apparatus includingan image pickup system and compression processing means for compressinga photographic image obtained from the image pickup system.

2. Description of the Related Art

FIG. 1 is a schematic block diagram showing the arrangement of aconventional example in which a video camera is integrated with adigital video tape recorder for digitally recording a video signal.

In the example shown in FIG. 1, an image pickup device 10 is providedwith a complementary color filter and performs pseudo-interlaced readingof electric charge stored by field storage. Specifically, as shown inFIG. 2, the image pickup device 10 is provided with a mosaic colorfilter made up of filter elements: white (W), cyan (Cy), yellow (Ye) andgreen (G). The image pickup device 10 outputs the added values of twoadjacent upper and lower lines, and a luminance signal processingcircuit 12 adds together the values of two adjacent pixels contained inthe output of the image pickup device 10, thereby forming a luminancesignal. A chrominance signal processing circuit 14 obtains differencesbetween the values of the two adjacent pixels, thereby formingcolor-difference signals.

More specifically, a luminance signal Yn obtained from a line #n and aluminance signal Yn+1 obtained from a line #(n+1) are as follows:Yn=(W+Cy)+(G+Ye)Yn+1=(W+Ye)+(G+Cy)and the associated chrominance signals Cn and Cn+1 are as follows:Cn=(W+Cy)−(G+Ye)Cn+1=(W+Ye)−(G+Cy)

If the characteristic of each filter element W is equal to the sum of R(red), G (green) and B (blue), i.e., R+G+B; the characteristic of eachfilter element Cy is equal to B+G; and the characteristic of each filterelement Ye is equal to Ye=R+G, the following equations are obtained:Yn=Yn+1=2R+4G+2BCn=2(B−G)Cn+1=2(R−G)

As shown in FIG. 2, the line numbers of adjacent upper and lower linesto be added together are made to differ between an even field and an oddfield, whereby an interlaced signal is obtained. To perform thisaddition, the image pickup device 10 needs to be provided with aphotoelectric conversion element having lines the number of which isequivalent to the number of lines per frame (in the NTSC system, 525lines). In the case of the NTSC system, in a line Lm of the image pickupdevice 10 shown in FIG. 1, m is 525.

A luminance signal Y formed by the luminance signal processing circuit12 and a chrominance signal C formed by the chrominance signalprocessing circuit 14 are stored in an image memory 16 under the controlof a memory control circuit 18. When image data for one frame are storedin the image memory 16, a motion detecting circuit 20 discriminatesbetween a moving image portion and a still image portion. An imagecompressing circuit 22 compresses the image data supplied from the imagememory 16, by using correlations present in the image. At this time, theimage compressing circuit 22 adaptively switches compression algorithmsbetween the still image portion and the moving image portion inaccordance with the detection result provided by the motion detectingcircuit 20.

The compressed image data is applied to an image recording device 24,and the image recording device 24 records the compressed image data on arecording medium.

A system control circuit 26 controls the entire arrangement inaccordance with the operation of a key operation device 28.

In the above-described arrangement, pseudo-interlaced field images arecompressed and recorded on the recording medium.

In the conventional example in which compression processing is performedafter field images are combined into a frame image, there is the problemthat if field images of a fast moving subject are combined into a frameimage, the resultant image may be blurred as shown in FIGS. 3( a) to3(c). FIG. 3( a) shows an odd field image, FIG. 3( b) shows thesucceeding even field image, and FIG. 3( c) shows the frame imageobtained by combining the odd and even field images.

Compression of an image utilizes correlations which appear in the imagein the space and time-axis directions thereof. In general, a framepicture the vertical line-to-line distance of which is smaller than thatof a field picture contains higher correlations. For this reason, asdescribed above, the conventional example adopts the compression methodof adaptively switching compression algorithms between a still imageportion and a moving image portion in a frame image.

As a result, the conventional example necessarily needs a motiondetecting circuit for detecting a still image portion and a moving imageportion, and, in addition, a substantially high detection accuracy isneeded. This problem makes it difficult to reduce the size of thecircuit.

As is known to those skilled in the art, since a conventionalcamera-integrated type of VTR does not conform to a plurality oftelevision standards, a plurality of camera-integrated types of VTRsmust be prepared and selectively used according to individual purposes.With the diversification of broadcasting systems, it becomes far morenecessary to exchange program software tapes between different nationsor to produce software conforming to multiple broadcasting systems.However, if a plurality of broadcasting systems are to be handled, aplurality of existing VTRs are needed, so that practical inconvenienceswill be encountered. For this reason, it has been desired to provide aVTR unit capable of conforming to multiple broadcasting systems.

As is also known to those skilled in the art, systems for recording andreproducing a digitized video signal are individually designed accordingto necessary image qualities or recordable/reproducible data rates.However, if system designs differ in coding sampling frequency which isa primary parameter for determining image quality, when one system isconnected to another video system, various problems occur.

Such conventional systems which are separately designed according toindividual required image qualities have the problem that it isimpossible to readily exchange image data between systems via media.

SUMMARY OF THE INVENTION

It is, therefore, an object of the present invention to provide an imageprocessing apparatus capable of solving the above-described problems.

To achieve the above object, in accordance with one aspect of thepresent invention, there is provided an image processing apparatus whichcomprises image pickup means having a plurality of photographic modes,compression processing means for performing compression processing of animage pickup signal outputted from the image pickup means, thecompression means having a plurality of compression modes, and selectingmeans for selecting one of the compression modes of the compressionprocessing means in accordance with a selected one of the photographicmodes of the image pickup means.

According to the above arrangement, it is possible to fully utilize theperformance of the compression processing means, so that it is possibleto realize a good image quality and a high compression ratio.

Another object of the present invention is to provide a video recordingapparatus, a video reproducing apparatus and a video recording andreproducing apparatus, such as a multimode-capable camera-integratedtype VTR capable of effecting camera photography, compression signalprocessing and video recording according to a plurality of televisionstandards.

To achieve the above object, in accordance with another aspect of thepresent invention, there is provided a video recording apparatus whichcomprises image pickup means capable of conforming to a plurality oftelevision standards, recording means for compressing data outputtedfrom the image pickup means at a compression ratio according to atelevision standard selected from the plurality of television standardsand recording on a recording medium compressed data and identificationinformation for identification of the selected television standard,setting means for setting the selected television standards, andcontrolling means for controlling the image pickup means and therecording means in accordance with a setting of the setting means.

To achieve the above object, in accordance with another aspect of thepresent invention, there is provided a video reproducing apparatus whichcomprises reproducing means for reproducing video data compressedaccording to a television standard and identification information foridentification of the television standard from a recording medium onwhich the video data and the identification information are recorded,and performing expansion processing of the video data, and controllingmeans for controlling the reproducing means on the basis of theidentification information reproduced from the recording medium.

To achieve the above object, in accordance with another aspect of thepresent invention, there is provided a video recording and reproducingapparatus which comprises a system converter for converting a firstvideo signal conforming to a first television standard into a secondvideo signal conforming to a second television standard, recording meansfor recording the first or second video signal on a recording medium,switching means for supplying to the recording means the first videosignal or the second video signal obtained from the system converter,reproducing means for reproducing the first or second video signal fromthe recording medium, and signal supplying means for supplying the firstvideo signal reproduced by the reproducing means to the systemconverter.

According to the first two aspects of the present invention, with asingle camera-integrated type VTR, it is possible to automaticallyperform recording processing and reproduction processing according to aplurality of compression modes which conform to a plurality oftelevision standards.

According to the third aspect of the present invention, the systemconverter is used during both recording and reproduction so that it ispossible to perform recording and reproduction of or provide a monitoroutput of a video signal according to a desired television standard.

In accordance with another aspect of the present invention which hasbeen made to solve the aforesaid problems, there is provided a videosystem which comprises recording means for recording video information,which is hierarchically coded, while forming a data recording area on arecording medium in accordance with a hierarchical structure of thevideo information and at least one recording mode of a plurality ofrecording modes each having a different recording processing, andreproducing means capable of setting a reproduction mode according tothe at least one recording mode and the hierarchical structure, orreproducing means capable of setting a reproduction mode within a rangeof the hierarchical structure irrespective of the at least one recordingmode.

According to the above aspect, it is possible to perform reproductionprocessing for reproducing recorded data from an information recordingmedium which is recorded in one of the plurality of recording modes, inan arbitrary reproduction mode in accordance with the conditions of areproduction side. The recorded data is reproduced from only a datarecording area which corresponds to a necessary information hierarchywithin information hierarchically recorded on a recorded tape.

The above and other objects, features and advantages of the presentinvention will become apparent from the following detailed descriptionof preferred embodiments of the present invention, taken in conjunctionwith the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic block diagram of the arrangement of a conventionalcamera-integrated type digital recording apparatus;

FIG. 2 is an explanatory view of the color-filter arrangement of theimage pickup device shown in FIG. 1 and the manner of reading ofelectric charge therefrom;

FIGS. 3( a), 3(b) and 3(c) are explanatory views of an image bluroccurring in a frame image as the result of a combination of fieldimages;

FIG. 4 is a schematic block diagram of the arrangement of an imageprocessing apparatus according to one embodiment of the presentinvention;

FIG. 5 is an explanatory view of the color-filter arrangement of theimage pickup device shown in FIG. 4 and the manner of reading ofelectric charge therefrom;

FIG. 6 is a schematic block diagram of the arrangement of acamera-integrated type video recording apparatus according to a secondembodiment of the present invention;

FIG. 7 is a schematic block diagram of one example of the broadcastingsystem conversion circuit shown in FIG. 6;

FIG. 8 is an explanatory, schematic view of a side panel system foraspect-ratio conversion;

FIG. 9 is an explanatory, schematic view of a squeeze system foraspect-ratio conversion;

FIG. 10 is an explanatory, schematic view of a letter box system foraspect-ratio conversion;

FIG. 11 is a comparative table of operating modes;

FIG. 12 is a schematic block diagram of the arrangement of the videocamera shown in FIG. 6;

FIG. 13 is a schematic block diagram of the arrangement of an imagecompressing circuit in the embodiment shown in FIG. 6;

FIG. 14 is an explanatory view of a block formed by the blocking circuitshown in FIG. 13;

FIG. 15 is an explanatory view of the pixel arrangements of an evenfield and an odd field;

FIG. 16 is an explanatory view of the output of the DCT circuit shown inFIG. 13;

FIG. 17 is an explanatory view of a zigzag scan;

FIG. 18 is a schematic block diagram of the arrangement of the recordingsystem of a digital video tape recorder;

FIG. 19 is a schematic view of a recording track pattern on a magnetictape;

FIG. 20 is a view of the data structure of a sub-code;

FIG. 21 is a schematic block diagram of the arrangement of thereproducing system of the digital video tape recorder;

FIG. 22 is a table of the recording characteristics of individual modes;

FIG. 23 is a schematic view showing a head for use in an SD-Low mode;

FIG. 24 is a schematic view showing tracks for one field in the SD-Lowmode;

FIG. 25 is a chart showing the timing of head switching which isperformed in the SD-Low mode;

FIG. 26 is a schematic view showing a head for use in an SD-High mode;

FIG. 27 is a schematic view showing tracks for one field in the SD-Highmode;

FIG. 28 is a chart showing the timing of head switching which isperformed in the SD-High mode;

FIG. 29 is a schematic view showing a head for use in an HD mode;

FIG. 30 is a schematic view showing tracks for one field in the HD mode;

FIG. 31 is a chart showing the timing of head switching which isperformed in the HD mode;

FIG. 32 is a flowchart of mode identification during reproduction;

FIG. 33 is a block diagram showing one example of a broadcasting systemconverter which serves as an up converter;

FIG. 34 is a schematic block diagram showing a video recording andreproducing apparatus according to another embodiment of the presentinvention;

FIG. 35 is a flowchart of a mode setting process according to anotherembodiment of the present invention;

FIG. 36 is an explanatory view of the principle of hill climbing focusadjustment;

FIG. 37 is a view showing the relationships between TV forms andfrequency characteristics;

FIG. 38 is a schematic view of a hierarchical VTR recording apparatusaccording to another embodiment of the present invention;

FIG. 39 is a conceptual view of the SD recording operation of thehierarchical VTR recording apparatus;

FIG. 40 is a conceptual view of the HD recording operation of thehierarchical VTR recording apparatus;

FIG. 41 is a schematic block diagram of a hierarchical VTR reproducingapparatus (HD) according to another embodiment of the present invention;

FIG. 42 is a conceptual view of the HD reproducing operation of thehierarchical VTR reproducing apparatus;

FIG. 43 is a conceptual view of SD reproduction from an HD recordedmedium to be performed by the hierarchical VTR reproducing apparatus;

FIG. 44 is a conceptual view showing the operation a hierarachical VTRto perform SD reproduction of an SD recording;

FIG. 45 is a track view showing the SD reproduction of an HD recordingby the hierarchical VTR;

FIG. 46 is a view showing two kinds of trace angles for HD and SD in thehierarchical VTR;

FIG. 47 is a list of the reproducing modes of a hierarchical VTR for SDsignals;

FIG. 48 is a list of the reproducing modes of a hierarchical VTR for HDsignals; and

FIG. 49 is a schematic view showing a hierarchical VTR reproducingapparatus (SD).

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present embodiments are based on the arrangement in which thepresent invention is applied to an image processing apparatus capable ofcoping with a plurality of photographic modes or television standards,as well as of performing recording and reproduction processings onhierarchically coded video signals.

Each of the embodiments of the present invention will be described belowwith reference to the accompanying drawings.

FIG. 4 is a schematic block diagram showing the arrangement of an imageprocessing apparatus according to one embodiment of the presentinvention. An image pickup device 30 is capable of selectivelyperforming a field reading operation and a frame reading operation, andthe color-filter arrangement of the image pickup device 30 is identicalto that of the image pickup device 10 shown in FIG. 1. Although theimage pickup device 10 is arranged to output the results of additions ofthe respective pairs of adjacent lines, the image pickup device 30 ofthis embodiment is capable of independently outputting a charge signalfrom each pair of adjacent lines, as shown in FIG. 5. The field readingoperation and the frame reading operation of the image pickup device 30primarily differ in reading frequency, and switching between the fieldreading operation and the frame reading operation is performed by ascanning switching circuit 32.

An even line processing circuit 34 computes charge signals read from theeven lines of the image pickup device 30, with respect to all theadjacent pixels, thereby forming a luminance signal Ye of an even field.An odd line processing circuit 36 computes charge signals read from theodd lines of the image pickup device 30, with respect to all theadjacent pixels, thereby forming a luminance signal Yo of an odd field.Also, a chrominance signal processing circuit 38 performs addition ofthe charge signals read from the even and odd lines of the image pickupdevice 30, with respect to all the adjacent lines, as well assubtraction of the same charge signals with respect to all the adjacentpixels, thereby a chrominance signal C.

Specifically, a luminance signal Yn obtained from a line #n of the oddfield and a luminance signal Yn+1 obtained from a line #(n+1) are asfollows:Yn=W+GYn+1=Cy+Yeand the associated chrominance signals Cn and Cn+1 are as follows:Cn=(W+Cy)−(G+Ye)Cn+1=(W+Ye)−(G+Cy)

If the characteristic of each filter element W is equal to the sum of R(red), G (green) and B (blue), i.e., R+G+B; the characteristic of eachfilter element Cy is equal to B+G; and the characteristic of each filterelement Ye is equal to Ye=R+G, the following equations are obtained:Yn=Yn+1=R+2G+BCn=2(B−G)Cn+1=2(R−G)

Regarding the even field as well, luminance signals and chrominancesignals can be obtained through similar computations.

Photoelectrically converted signals, which have been obtained from linesL1 to Lm (m=525 in the NTSC system) corresponding to horizontal scanninglines which constitute a television picture, are applied to the evenline processing circuit 34, the odd line processing circuit 36 and thechrominance signal processing circuit 38, and the luminance signal Yeand the luminance signal Yo as well as the chrominance signal C which iscommon to the signals Ye and Yo are formed.

A frame photographic image outputted from the image pickup device 30 isstored in an image memory 42 in the following manner. The image pickupdevice 30 outputs the photoelectrically converted signals of all thelines in the order of the lines, or simultaneously outputs therespective photoelectrically converted signals of the even lines and theodd lines in line order. Since a switch 44 is open, the luminance signalYe formed by the even line processing circuit 34 passes through an adder40 without being subject to addition, and is applied to the image memory42. The luminance signal Yo formed by the odd line processing circuit 36and the chrominance signal C formed by the chrominance signal processingcircuit 38 are also applied to the image memory 42. The image memory 42stores the luminance signals Ye and Yo and the chrominance signal Cunder the control of a memory control circuit 46. Thus, a frame imageobtained by one exposure cycle is stored in the image memory 42. Theabove-described operation is hereinafter referred to as the “frame imagepickup mode”.

The operation of combining field photographic images obtained by theimage pickup device 30 to form a frame image and storing the resultantframe image in the image memory 42 is performed in the following manner.The image pickup device 30 outputs the photoelectrically convertedsignals of all the lines in the order of the lines, or simultaneouslyoutputs the respective photoelectrically converted signals of the evenlines and the odd lines in line order. In this reading stage, image datafor an odd field is first stored in the image memory 42. Specifically,the image memory 42 stores the luminance signal Yo of the odd fieldwhich is formed by the odd line processing circuit 36 as well as thechrominance signal C formed by the chrominance signal processing circuit38.

During the next field, the switch 44 is closed and the image memory 42is made to operate in a read modify write mode, thereby feeding thestored luminance signal Yo back to the adder 40 through the switch 44.Similarly to the aforesaid odd field, the image pickup device 30 outputsthe photoelectrically converted signals of all the lines in the order ofthe lines, or simultaneously outputs the respective photoelectricallyconverted signals of the even lines and the odd lines in line order. Inthis reading stage, the even line processing circuit 34 and thechrominance signal processing circuit 38 operate, and the adder 40 addsthe luminance signal Yo fed back from the image memory 42 to theluminance signal Ye formed by the even line processing circuit 34. Thus,it is possible to obtain a result similar to the result of two-lineaddition described previously in connection with the conventionalexample. The image memory 42 sequentially stores the output of the adder40 and the output of the chrominance signal processing circuit 38 intopredetermined memory locations. Thus, a frame image in which the fieldimages obtained through two exposure cycles are combined is stored inthe image memory 42. The above-described operation is referred to as the“field image pickup mode”.

When the image data for one frame is stored in the image memory 42, theimage compressing circuit 48 compresses the image data stored in theimage memory 42 in a compression mode according to a control signalsupplied from a system control circuit 52. For example, according towhich of the frame image pickup mode and the field image pickup mode isactive, a block to be formed by block coding such as DCT (discretecosine transform), which block is a main unit in image compressionprocessing, is determined as a field-based block or a frame-based block.

The compressed image data outputted from the image compressing circuit48 is applied to an image recording device 50, and the image recordingdevice 50 records the compressed image data on a recording medium.

The system control circuit 52 controls the entire apparatus inaccordance with the operation of a key operation device 54.

As a matter of course, it is also possible to select a compressionsystem from among various compression coding systems other than DCT. Forexample, if a DPCM system which is one kind of predictive coding systemis employed, in the case of the field image pickup mode in which ahigher correlation appears in a horizontal direction than in a verticaldirection, compression is performed by a horizontal DPCM system ofperforming a differential computation in the horizontal direction,while, in the case of the frame image pickup mode in which a highercorrelation appears in a vertical direction than in a horizontaldirection, compression is performed by a vertical DPCM system ofperforming a differential computation in the vertical direction.

In the above-described embodiment, switching between field-based imagecompression and block-based image compression is performed according towhich of the field image pickup mode and the frame image pickup mode hasbeen selected. However, as a matter of course, it is also possible toadopt an arrangement capable of selecting the field image pickup mode orthe frame image pickup mode in accordance with whether the field-basedimage compression or the frame-based image compression has beenselected. In other words, it is possible to reduce a degradation ofimage quality by linking the field image pickup mode or the frame imagepickup mode with the field-based image compression or the frame-basedimage compression.

Another embodiment of the present invention will be described below inwhich the present invention is applied to a camera-integrated type videorecording apparatus which is compatible to an existing broadcastingsystem (for example, the NTSC system (SD)) and a high-definitiontelevision system (for example, a “high-vision” system (HD)) and ofperforming camera photography, compression processing and recordingwhich is intended to two layers of image structures (SD and HD) eachhaving a different image-quality design. FIG. 6 is a schematic blockdiagram of the arrangement of the entire apparatus.

Referring to FIG. 6, an HDTV camera 60 is arranged to output ahigh-definition television signal, i.e., an HD signal. According to atelevision studio standard, the number of effective pixels per picked-upimage is 1,920 pixels in the horizontal direction and 1,035 pixels inthe vertical direction, and the sampling frequency is 75.3 MHz. Theoutput of the camera 60 enters two different paths. The signal which hasentered one path is applied to an image pickup mode selecting circuit 64via a broadcasting system conversion circuit 62, while the signal whichhas entered the other paths is directly applied to the image pickup modeselecting circuit 64.

The broadcasting system conversion circuit 62 is a down converter forconverting an HD signal into a signal conforming to any of the NTSC, PALand SECAM systems which are standard broadcasting systems (hereinafterreferred to as the “SD system”).

One example of the broadcasting system conversion circuit 62 forconverting an HD signal into an NTSC signal is shown in FIG. 7. Sincethe HD signal has an aspect ratio of 16:9 and the SD signal has anaspect ratio of 4:3, an aspect ratio conversion circuit 100 converts the16:9 aspect ratio into the 4:3 aspect ratio.

Specifically, it is possible to select a desired system from among aside panel system in which the right and left end portions of ahigh-vision image are omitted (refer to FIG. 8), a squeeze system (or afull-display system) in which a high-vision image is compressed in thehorizontal direction (refer to FIG. 9), and a letter box system in whichan image of 16:9 aspect ratio is displayed in a picture of 4:3 aspectratio (refer to FIG. 10). In the case of the letter box system, althoughempty spaces are formed in the top and bottom portions of a picture,they are displayed in black. If the HD signal is to be converted intothe NTSC system, the side panel system or the squeeze system issuitable, while the letter box system is suited to a case where it isdesired to fully utilize the photographic field angle of the HD camera60.

The HD signal and the SD signal greatly differ in the number ofhorizontal scanning lines. A number-of-scanning-lines conversion circuit102 converts the number of horizontal scanning lines of the HD output ofthe aspect ratio conversion circuit 100 into the number of horizontalscanning lines conforming to the SD system. For example, signals for therequired horizontal scanning lines are formed by a verticalinterpolation filter.

A field frequency conversion circuit 104 converts the field frequency ofthe output of the number-of-scanning-lines conversion circuit 102 (60 HZin the case of the high-definition signal) into a field frequencyconforming to the SD system (59.94 Hz in the case of the NTSC system).This frequency conversion can be executed at real time by a time-basecorrector having a function similar to a frame synchronizer.

In a generally used frame synchronizer, in the case of a capacity of oneframe memory, one frame cap occurs at intervals of approximately 33seconds and causes an unnatural discontinuity in a moving image. Incontrast, motion-adaptive type field frequency conversion detectsmotions and scene changes by using a frame difference signal, andperforms frame skipping if the following four conditions are satisfied:

-   -   1) an image signal indicates a still image;    -   2) a scene change has occurred;    -   3) a moving-image area is comparatively small; and    -   4) a frame buffer memory is full.

An NTSC encoder 106 converts the output of the field frequencyconversion circuit 104 into a television signal conforming to the NTSCsystem.

In the present embodiment, in the case of the SD system as well, it ispossible to select a high image quality mode for business use(horizontal resolution: approximately 450 lines) and a standard imagequality mode for home use (horizontal resolution: approximately 230lines). The former mode is hereinafter referred to as the “SD-Highmode”, while the latter mode is hereinafter referred to as the “SD-Lowmode”. A mode for recording the HD signal is hereinafter referred to asthe “HD mode”. An operator can selectively set the HD mode, the SD-Highmode or the SD-Low mode by means of an operation panel 92, and a systemcontrol circuit 90 controls the image pickup mode selecting circuit 64in accordance with the mode set by the operator. The image pickup modeselecting circuit 64 selects the HD signal output of the camera 60 inthe case of the HD mode or the output of the broadcasting systemconversion circuit 62 in the case of the SD-High mode or the SD-Lowmode.

The signal selected by the image pickup mode selecting circuit 64 isapplied to a compression circuit 66. The compression circuit 66 isprovided with a plurality of compression modes (in the shown example, amode #1 and a mode #2) so that a compression ratio and a compressioncoding system can be individually selected. The compression ratio isselected from among, for example, 1/4, 1/8, 1/16 and 1/32. Thecompression coding system is selected from, for example, DCT, DPCM,Hadamard transform and ADRC. In the arrangement shown in FIG. 6, forexample, DCT and DPCM may be allocated to the compression mode #1 andthe compression mode #2, respectively, or the compression ratio may bevaried under a single compression coding system.

The compression circuit 66 compresses the output of the image pickupmode selecting circuit 64 in the compression mode #1 as well as in thecompression mode #2. The data compressed in the compression mode #1 andthe compression mode #2 are both applied to a compression mode selectingcircuit 68. The compression mode selecting circuit 68 selects either oneof the data compressed in the compression mode #1 and the datacompressed in the compression mode #2, in accordance with a controlsignal supplied from the system control circuit 90, and applies theselected compressed data to a recording processing circuit 70.

The modes to be selected by the image pickup mode selecting circuit 64and the compression mode selecting circuit 68 are closely related tofactors, such as a recording time or image quality to be selected for arecording system and the quality of an image to be picked up by thecamera 60 or a mode set for the camera 60. The modes are automaticallydetermined in association with such factors.

According to a relationship with a recording system which will bedescribed later, it is desirable that the data rates of imagescompressed in the respective compression modes have a relationshiprepresented by an integer ratio, for example, 50 Mbps in the HD mode, 25Mbps in the SD-High mode and 12.5 Mbps in the SD-Low mode, as shown inFIG. 22.

A recording processing circuit 70 applies recording processing, such asmodulation, to the compressed data supplied from the compression modeselecting circuit 68, divides the processed data into two channels, andoutputs the divided data to the respective channels. Recordingamplifiers 72 a and 72 b amplify the respective outputs of the recordingprocessing circuit 70. A rotary drum 74 is provided with two pairs ofheads 76 a, 76 b and 78 a, 78 b. The outputs of the recording amplifiers72 a and 72 b are respectively recorded on a magnetic tape 80 by theheads 76 a, 76 b and 78 a, 78 b. The width of each track formed on themagnetic tape 80 is the same for any of the HD mode, the SD-High modeand the SD-Low mode.

A servo circuit 82 causes a drum motor 84 to rotate the rotary drum 74at a predetermined rotational speed, and also causes a capstan motor 86to rotate a capstan 88, thereby causing the magnetic tape 80 to run at apredetermined speed. The system control circuit 90 supplies to the servocircuit 82 a target value based on an operation mode according to anoperation instruction inputted through the operation panel 92.

FIG. 11 shows the relationships between the modes selected through theoperation panel 92 and the image pickup systems, the compression ratiosand the recording data rates.

The camera 60 shown in FIG. 6 will be described in detail with referenceto FIG. 12. A photographic lens unit 110 includes a focusing lens 110 afor adjusting its focal length and a zooming lens 110 b for varying itsmagnification, and focuses an optical image of a subject on thephotoelectric conversion face of an image pickup device 114 via an iris112. A predetermined color filter 116 is attached to the photoelectricconversion face of the image pickup device 114.

The image pickup device 114 operates in accordance with a clock suppliedfrom a clock generating circuit 118, and outputs a charge signal. Theoutput of the image pickup device 114 is noise-reduced by a CDS circuit120 and is then gain-controlled by an AGC circuit 122. The output of theAGC circuit 122 is applied to an exposure control circuit 124, a focuscontrol circuit 126, a white balance adjustment circuit 128 and a colorprocessing circuit 130.

A driving circuit 132 a and a motor 132 b drive the focusing lens 110 aalong the optical axis, a driving circuit 134 a and a motor 134 b drivethe zooming lens 110 b along the optical axis, and a driving circuit 136a and a motor 136 b drive the iris 112 to cause it to open and close.

A system control circuit 138 controls the gain of the AGC circuit 122 inaccordance with the output of the exposure control circuit 124, and alsocontrols the degree of opening of the iris 112 by means of the drivingcircuit 136 a and the motor 136 b. The system control circuit 138adjusts the position of the focusing lens 110 a along the optical axisby means of the driving circuit 132 a and the motor 132 b in accordancewith the output of the focus control circuit 126, thereby placing thephotographic lens unit 110 into an in-focus state.

The white balance adjustment circuit 128 forms a control signal forwhite balance adjustment, and the system control circuit 138 controlsthe color processing circuit 130 in accordance with the output of thewhite balance adjustment circuit 128. The color processing circuit 130generates a white-balanced luminance signal Y as well ascolor-difference signals R-Y and B-Y from the output of the AGC circuit122. A process circuit 140 converts into RGB signals the luminancesignal Y and the color-difference signals R-Y and B-Y outputted from thecolor processing circuit 130, and an encoder 142 generates a compositesignal from the output of the process circuit 140. The encoder 142 alsooutputs video signals in Y/C separation form.

The outputs of the color processing circuit 130 and the outputs of theprocess circuit 140 may of course be outputted to the outside ascomponent outputs.

A display generating circuit 144 generates display signals indicative ofoperation mode, time and date and the like under the control of thesystem control circuit 138, and an adder 146 adds the output of thedisplay generating circuit 144 to the composite output of the encoder142 and applies a signal indicative of the addition result to anelectronic viewfinder 148. Thus, a photographer can view various kindsof information together with a subject to be photographed, on the screenof the electronic viewfinder 148. Further, since a composite signal isinputted to the electronic viewfinder 148 from a reproducing systemwhich will be described later, it is possible to view a reproducedimage.

The photographer also can set photographic conditions, such asphotographic mode, photographic magnification and exposure, by operatingan operation key 150.

If photographic image information is digitally processed in the camerashown in FIG. 12, each output signal may of course be outputted indigital form. If analog outputs are needed, a D/A converter and aband-limiting low-pass filter may be provided at suitable locations.

The compression processing performed in the compression circuit 66 shownin FIG. 6 will be described below in brief. Compression of an image isto reduce the amount of data by removing the redundancy of the image.Compression of a still image utilizes the spatial redundancy of theimage. Compression of a moving image utilizes its temporal redundancy inaddition to its spatial redundancy, but the basic principles are basedon still image compression techniques.

The element techniques of moving-image compression which conforms to,for example, the MPEG (Moving Picture Expert Group) standard, are DCT(discrete cosine transform) processing, quantization processing, codingprocessing and motion adaptation processing. Expansion can be regardedas the inverse process of compression. The DCT (discrete cosinetransform) processing, the quantization processing and the codingprocessing are common to both the moving-image compression andstill-image compression. These techniques will be described below inbrief in that order.

DCT converts spatial coordinates into frequencies. As the pre-processingof compression, an input picture is blocked into a pixel group ofapproximately 8×8 pixels. Multiplication processing using DCTcoefficients is performed in units of blocks, whereby space data areconverted into frequency data. Although the amount of data is notreduced by DCT alone, it is possible to concentrate data which is widelydispersed in the picture. In other words, an image has a generaltendency for more energy to concentrate on a lower spatial frequencyside, and DCT performs the function of increasing a compression ratiofor substantial compression processing to be executed at the succeedingstages.

The quantization processing rounds off the word lengths of coefficientswhich have been converted into frequencies by the DCT processing,thereby reducing the amount of data. For example, a data coefficientindicative of each frequency component produced by DCT is divided by anappropriate value, and the figures below the decimal point of theresultant value are omitted. By omitting the figures below the decimalpoint, it is possible to reduce the number of bits which are required torepresent each coefficient data, whereby the total amount of data can bereduced. By setting a divisor for each frequency component, it ispossible to increase the compression ratio while retaining the requiredimage quality.

The coding processing assigns to each data a length code correspondingto the occurrence frequency of the data. First, a zigzag scan of thequantized data is performed to convert a two-dimensional data array intoa unidimensional data string. The two-dimensional data array is scannedin a zigzag manner from a DC component toward horizontal and verticalhigher-frequency components, whereby the data is rearranged. By runlength coding, the same numbers (mainly, zeros) which continuously occurare replaced with one code which collectively represents such continuousoccurrence. If the data which appear after a particular location are allzeros, an end code is assigned to the data. This code indicates that ifit is detected in a block, the transfer of data from the block isbrought to an end, and realizes a great, data reduction effect.

By assigning codes of fewer bits to numbers having higher occurrencefrequencies, the substantial total number of coding bits can be reduced.

The motion adaptation processing adds the technique of detecting andpredicting a motion to still-image compression. The element techniquesincludes motion detection, motion predictive compensation andinterlacing coding. The motion adaptation processing will be describedbelow with illustrative reference to the case of compression of a movingimage conforming to a television broadcasting standard.

In the motion detection, image data is delayed by a time whichcorresponds to an integer multiple of a field (or frame) period, as by aframe memory, and two field (frame) pictures are compared in a time-axisdirection, thereby detecting a motion. As well-known motion detectingmethods, there are a method of obtaining the amount of motion as theabsolute value of the difference in luminance data between pictures anda method of computing the travel of a two-dimensional coordinate pointhaving a highest correlation, thereby detecting a motion vector.

The motion predictive compensation predicts a motion of an image by thedetected motion vector and transmits only the difference between apredicted image and an actual image as compensation data. Accordingly,it is possible to reduce the amount of information to be transferred.Specifically, it is possible to reduce prediction errors in the case ofimages, such as an image which contains a large still-image portion andmoves to a small extent, an image which moves moderately and an imagewhich is rectilinearly travelling. Accordingly, a high compressioneffect can be achieved.

The interlacing coding forms a pixel block for compression processing inunits of fields. A television signal, such as an NTSC television signal,has an interlaced structure in which the scanning lines of odd and evenfields are alternately disposed. An odd field made up of 262.5 odd linesand an even field made up of 262.5 even lines are paired to form a framepicture made up of 525 lines.

If an odd field and an even field are simply combined when the amount ofmotion of a subject in a picture is large, a frame image blurs and isvisually extremely impaired. In a blurred portion of the picture, avertical spatial correlation is lowered, so that no high compressionratio can be achieved by compression coding processing. If the amount ofmotion is small, this problems does not occur.

For this reason, if the amount of motion is small, a pixel block forcompression processing is formed within a frame picture, while if theamount of motion is greater than a predetermined amount, a pixel blockfor compression processing is formed within a field picture.

FIG. 13 is a schematic block diagram showing the arrangement of an imagecompressing circuit which adopts the above-described moving imagecompression processing techniques. Referring to FIG. 13, an SD or HDsignal outputted from the image pickup mode selecting circuit 64 shownin FIG. 6 is inputted through an input terminal 200. The video signalinputted through the input terminal 200 is inputted to an input buffer202 and a motion detecting circuit 204. The input buffer 202 functionsas 1-frame-period delay means, and its output is applied to a blockingcircuit 206 and the motion detecting circuit 204.

The motion detecting circuit 204 performs the above-described comparisoncomputation on the video signal supplied from the input terminal 200 andthe video signal outputted from the input buffer 202, thereby detectinga motion vector. The motion detecting circuit 204 outputs informationindicative of the amount and direction of the motion to a system controlcircuit 220. On the basis of the motion vector information, the systemcontrol circuit 220 determines whether compression processing is to beperformed in units of fields or in units of frames, and applies theresultant field/frame selection information to the blocking circuit 206.

The blocking circuit 206 blocks the output image of the input buffer 202into 8 pixels×8 pixels as shown in FIG. 14, in the units of fields orframes according to the field/frame selection signal supplied from thesystem control circuit 220. FIG. 15 shows the pixel arrangements of oddand even fields within one frame.

A DCT circuit 208 performs discrete cosine transform of the blockedpixel data supplied from the blocking circuit 206. By this discretecosine transform, the image data is converted into coefficient datawhich is represented as a block of 8 pixels×8 pixels in a frequencyspace as shown in FIG. 16. As the general nature of an image, a DCcoefficient and lower-frequency AC components have larger values, whilehigher-frequency AC components have values close to zero.

The output of the DCT circuit 208 is applied to a quantizing circuit 210and a coefficient setting circuit 212. The coefficient setting circuit212 sets a quantizing coefficient for the quantizing circuit 210 inaccordance with a control signal supplied from the system controlcircuit 220 and the output of the DCT circuit 208. The quantizingcircuit 210 quantizes the output of the DCT circuit 208 with thequantizing coefficient set by the coefficient setting circuit 212.Specifically, data coefficients for the individual frequency componentsare divided by adequate divisors, and the figures below the decimalpoints of the respective results are omitted to reduce the number ofbits. Incidentally, the divisors may differ among the individualfrequency components.

A coding circuit 214 first performs a zigzag scan of the output of thequantizing circuit 210 in the zigzag manner shown in FIG. 17 from a DCcomponent toward horizontal and vertical higher-frequency components asshown in FIG. 17, thereby unidimensionally rearranging the data. Afterthen, the coding circuit 214 replaces continuing zeros with apredetermined code indicative of the number of the continuing zeros byrun length coding. As described previously, if all the data which appearafter a particular location are zeros, the coding circuit 214 assigns anend code to the data. The coding circuit 214 also assigns a short codeto data the occurrence frequency of which is high, by variable lengthcoding. Thus, the amount of data can be greatly reduced.

An amount-of-data calculating circuit 218 calculates the amount of thecoded data generated by the coding circuit 214 and supplies the resultto the system control circuit 220. The system control circuit 220 causesthe coefficient setting circuit 212 to generate a quantizing coefficientwhich is selected so that the amount of coded data to be generated bythe coding circuit 214 becomes a predetermined value.

The output of the coding circuit 214 is supplied to an output buffer216. The output buffer 216 supplies the output of the coding circuit 214to a rear-stage circuit at a data rate. The output buffer 216 alsosupplies information indicative of its internal data occupation ratio tothe system control circuit 220. The system control circuit 220 controlsthe coefficient setting circuit 212 so that this occupation ratiobecomes stable in the neighborhood of a predetermined value in order toprevent an overflow or a data shortage from occurring in the outputbuffer 216. Specifically, if the data occupation ratio is high, thesystem control circuit 220 causes the coefficient setting circuit 212 toset a large coefficient (divisor), whereas if the data occupation ratiois low, the system control circuit 220 causes the coefficient settingcircuit 212 to set a small coefficient (divisor).

In the arrangement shown in FIG. 13, the system control circuit 220controls the coefficient setting circuit 212 in accordance with theamount of coded data generated by the coding circuit 214 (the output ofthe amount-of-data calculating circuit 218) and the data occupationratio of the output buffer 216. An operator can instruct, through a modeselecting member 222, the system control circuit 220 to performswitching among the compression ratios (target values), the compressionsystems and the like. Of course, the system control circuit 220 canadaptively control the compression ratios (target values), thecompression systems and the like in accordance with the result of thedetection of a motion of an image and an operation mode set by the modeselecting member 222, whereby it is possible to efficiently compress amoving image. As a matter of course, by changing the coefficient to beset by the coefficient setting circuit 212, it is also possible to varythe compression ratio.

The recording system for recording a signal supplied from the camerasystem of FIG. 12 will be described below in detail. FIG. 18 is adetailed block diagram showing the arrangement of the recording system.In the shown arrangement, a system control circuit 336 is substantiallyidentical to the system control circuit 138 of the camera system.

An A/D converter 300 converts the luminance signal Y into a digitalsignal, while an A/D converter 302 converts the chrominance signal Cinto a digital signal. The luminance signal Y and the chrominance signalC are those supplied from the camera system described previously withreference to FIG. 12. Of course, if digital processing is alreadyperformed in the camera system, neither of the A/D converters 300 and302 is needed.

A multiplexer 306 of a video data processing circuit 304 multiplexes theoutputs of the A/D converters 300 and 302 and outputs the multiplexeddata to an amount-of-information compressing circuit 308. Theamount-of-information compressing circuit 308 compresses the multiplexeddata by using a compression system and a compression ratio according tomode information supplied from the system control circuit 336. Theamount-of-information compressing circuit 308 is substantially identicalto the circuit described above with reference to FIG. 13. Of course, itis also possible to adopt a circuit arrangement for individuallycompressing the amounts of information of luminance data and chrominancedata without multiplexing these data in the multiplexer 306.

A shuffling circuit 310 rearranges the output data string of theamount-of-information compressing circuit 308 in accordance withappropriate rules, thereby preventing a transmission error from easilyoccurring in the data string. This shuffling operation also has theeffect of making uniform the uneven distribution of the amount ofinformation in a picture which is based on the presence of dense andsparse portions in the picture. The execution of the shuffling operationat a stage preceding the compression of the amount of information isconvenient for variable length coding, such as run length coding.

An ID adding circuit 312 adds identification (ID) information forrestoring the data shuffled by the shuffling circuit 310. Thisidentification information also contains mode information indicative ofmodes used for recording (the kind of compression system and the like),and is used as auxiliary information for expansion processing duringreproduction. An ECC adding circuit 314 adds an error-correcting code tothe output data of the ID adding circuit 312.

The video data subjected to the above-described processing in the videodata processing circuit 304 is distributed into two channels by a datadistributing circuit 316.

An A/D converter 318 converts the L-channel signal of a stereophonicaudio signal into a digital signal, while an A/D converter 320 convertsthe R-channel signal into a digital signal. A multiplexer 324 of anaudio data processing circuit 322 multiplexes the outputs of the A/Dconverters 318 and 320 and outputs the multiplexed data to anamount-of-information compressing circuit 326. The amount-of-informationcompressing circuit 326 compresses the multiplexed data by using acompression system and a compression ratio according to mode informationsupplied from the system control circuit 336.

If the recording rate of video data is large, as in the case of an HDsignal, audio information may also be recorded on a recording mediumwithout compression.

A shuffling circuit 328 rearranges the output data string of theamount-of-information compressing circuit 326 in accordance withappropriate rules, thereby preventing a transmission error from easilyoccurring in the data string. An ID adding circuit 330 addsidentification (ID) information for restoring the data shuffled by theshuffling circuit 328. This identification information also containsmode information indicative of modes used for recording (the kind ofcompression system and the like), and is used as auxiliary informationfor expansion processing during reproduction. An ECC adding circuit 332adds an error-correcting code to the output data of the ID addingcircuit 330.

The audio data subjected to the above-described processing in the audiodata processing circuit 322 is distributed into two channels by a datadistributing circuit 334.

A pilot generating circuit 338 generates a pilot signal for trackingservo, and a sub-code generating circuit 340 generates auxiliary data tobe recorded simultaneously with the video and audio data. Such auxiliarydata contains, for example, an address code for searching for a positionon a magnetic tape and the indexes of a program to be recorded.

A multiplexer 342 multiplexes one of the channel outputs of each of thedata distributing circuits 316 and 334, the pilot signal outputted fromthe pilot generating circuit 338, and the sub-code data generated by thesub-code generating circuit 340. A multiplexer 344 multiplexes the otherchannel output of each of the data distributing circuits 316 and 334,the pilot signal outputted from the pilot generating circuit 338, andthe sub-code data generated by the sub-code generating circuit 340. Inthe case of time-base multiplexing, the multiplexing of the pilot signalmay be performed in accordance with an area division ATF system which iswell known in the field of digital audio tape recorders.

Digital modulating circuits 346 and 348 digitally modulate therespective outputs of the multiplexers 342 and 344 by means of, forexample, 8-10 conversion and an NRZI method.

The recording system according to the present embodiment is providedwith two pairs of magnetic heads. A head switching circuit 350 switchesthe output of the modulating circuit 346 between recording amplifiers354 and 356 in accordance with a control signal supplied from a servocircuit 378. A head switching circuit 352 switches the output of themodulating circuit 348 between recording amplifiers 358 and 360 inaccordance with a control signal supplied from the servo circuit 378.The outputs of the recording amplifiers 354, 356, 358 and 360 arerespectively applied to magnetic heads 364 a, 364 c, 364 b and 364 d ofa rotary drum 362, whereby they are recorded on a magnetic tape 366.FIG. 19 shows one example of the track pattern of the magnetic tape 366.Each of the tracks contains a pilot signal P, audio data A, sub-code Sand video data V. FIG. 20 shows the detailed data structure of thesub-code S.

The servo circuit 378 controls the rotation of the rotary drum 362 andthe running of the magnetic tape 366 as well as the head switchingoperations of the head switching circuits 350 and 352. Specifically, arotation detector (FG) 376 for detecting the rotation of a capstan motor374 for causing the magnetic tape 366 to run is connected to the capstanmotor 374, and the servo circuit 378 controls, according to the outputof the rotation detector (FG) 376, the capstan motor 374 to cause it torotate at a predetermined rotational speed.

Also, a drum motor 368 rotates the rotary drum 362, a rotation detector(FG) 370 detects the rotational speed of the drum motor 368, and arotational phase detector (PG) 372 detects the rotational phase of therotary drum 362. The servo circuit 378 drives, according to the outputsof the rotation detector (FG) 370 and the rotational phase detector (PG)372, the drum motor 368 to cause the rotary drum 362 to rotate at apredetermined rotational speed. The servo circuit 378 also controls thehead switching operations of the head switching circuits 350 and 352 inaccordance with the output of the rotational phase detector (PG) 372.

The system control circuit 336 controls the entire recording system inaccordance with an instruction inputted through an operation panel (notshown) and on the basis of the operating state of each part.

The functions of the system control circuit 336 and the servo circuit378 are realized by one microcomputer chip.

The reproducing system will be described below in detail with referenceto FIG. 21. In FIG. 21, identical reference numerals are used to denoteconstituent elements identical to those shown in FIG. 18. Specifically,in a manner similar to the recording operation, the servo circuit 378causes the magnetic tape 366 to run at a predetermined speed by means ofthe capstan motor 374 as well as causes the rotary drum 362 to rotate ata predetermined rotational speed and in a predetermined rotational phaseby means of the capstan motor 374.

The outputs of the magnetic heads 364 a, 364 c, 364 b and 364 d arerespectively amplified by reproducing amplifiers 380, 382, 384 and 386,and the outputs of the reproducing amplifiers 380, 382 and 384, 386 arerespectively applied to head switching circuits 388 and 390. Inaccordance with control signals supplied from the servo circuit 378, thehead switching circuit 388 switches the outputs of the reproducingamplifiers 380 and 382 therebetween, while the head switching circuit390 switches the outputs of the reproducing amplifiers 384 and 386therebetween. Demodulating circuits 392 and 394 respectively digitallydemodulate the outputs of the head switching circuits 388 and 390 by aredundancy detecting method, such as a differential detecting method, anintegral detecting method or Viterbi decoding, and output two-levelsignals. Each of the outputs of the demodulating circuits 392 and 394 ismade of information which includes video information, audio information,a pilot signal and sub-code information in a time division multiplexedstate.

Signal distributing circuits 396 and 398 supply the respective outputsof the demodulating circuits 392 and 394 to predetermined circuits: thatis to say, the video information is supplied to a data integratingcircuit 406, the audio information is supplied to a data integratingcircuit 424, the pilot signals are supplied to a pilot detecting circuit400, and the sub-code information is supplied to a sub-code detectingcircuit 402.

The pilot detecting circuit 400 detects as an error signal the timedifference between the pilot signal and a timing reference signalcorresponding to an off-track amount relative to the right and lefttracks, and supplies the error signal to the servo circuit 378. Theservo circuit 378 adjusts a tape transporting speed in accordance withthe error signal. The error signal can also be used as auxiliaryinformation for identification of a recording mode.

A sub-code detecting circuit 402 decodes the content of the sub-codefrom each of the S outputs of the signal distributing circuits 396 and398, and supplies the result to a system control circuit 404. The systemcontrol circuit 404 controls each part in accordance with the content ofthe reproduced sub-code.

The data integrating circuit 406 integrates the video informationsupplied from the signal distributing circuits 396 and 398 via twolines, and outputs the integrated video information to a video datareproducing circuit 408.

In the video data reproducing circuit 408, an error correcting circuit410 corrects an error which has occurred during recording orreproduction. If the error cannot be corrected, the error correctingcircuit 410 performs correction of the error by using interpolation. AnID detecting circuit 412 detects the ID added by the ID adding circuit312 during recording, and supplies the ID to the system control circuit404. A de-shuffling circuit 414 restores the data string rearranged bythe shuffling circuit 310, and an amount-of-information expandingcircuit 416 expands the data compressed by the amount-of-informationcompressing circuit 308, in accordance with the mode informationsupplied from the system control circuit 404, thereby restoring theoriginal image data. A data separating circuit 418 separates theoriginal image data into luminance data and chrominance data andsupplies the respective data to D/A converters 420 and 422. The dataseparating circuit 418 also outputs the digital image data to theoutside.

The D/A converter 420 converts the luminance data into an analog signal,while the D/A converter 422 converts the chrominance data into an analogchrominance signal. The analog signals are both outputted to theoutside, and are also converted into a composite signal, which isinputted to the adder 146 of FIG. 12. An operator can view a reproducedimage in the electronic viewfinder 148.

The data integrating circuit 424 integrates the audio informationsupplied from the signal distributing circuits 396 and 398 via twolines, and outputs the integrated audio information to an audio datareproducing circuit 426.

In the audio data reproducing circuit 426, an error correcting circuit428 corrects an error which has occurred during recording orreproduction. If the error cannot be corrected, the error correctingcircuit 428 performs correction of the error by using interpolation. AnID detecting circuit 430 detects the ID added by the ID adding circuit330 during recording, and supplies the ID to the system control circuit404. A de-shuffling circuit 432 restores the data string rearranged bythe shuffling circuit 328, and an amount-of-information expandingcircuit 434 expands the data compressed by the amount-of-informationcompressing circuit 326, in accordance with the mode informationsupplied from the system control circuit 404, thereby restoring theoriginal audio data. A data separating circuit 436 separates theoriginal audio data into L-channel audio data and R-channel audio dataand supplies the respective data to D/A converters 438 and 440. The dataseparating circuit 436 can also output the digital audio data to theoutside.

The D/A converter 438 converts the L-channel audio data into an analogsignal, while the D/A converter 440 converts the R-channel audio datainto an analog signal. The analog signals are both outputted to theoutside.

As described previously, the present embodiment is provided with thethree modes: the HD mode, the SD-High mode and the SD-Low mode. Sincerecording track patterns differ among the three modes, modeidentification information is recorded in sub-code areas so thatreproduction from tracks can be correctly performed in the case of anyof the three modes. The recording track patterns and mode identificationmethods for the respective modes will be described below. FIG. 22 showsmagnetic tape running speeds, the number of tracks per field andcompression ratios for the respective modes.

The SD-Low mode serves as a long-time recording mode for the SD signal.Out of the four magnetic heads Ha, Hb, Hc and Hd shown in FIG. 23, onlythe magnetic heads Ha and Hb are used, and five tracks per field areformed as shown in FIG. 24. FIG. 25 shows the timing of head switching.Recording current is alternately applied to the magnetic heads Ha and Hbeach time a drum PG pulse goes high while a rotary drum is being rotatedat 150 rps.

In the SD-High mode, out of the four magnetic heads Ha, Hb, Hc and Hdshown in FIG. 26, only the magnetic heads Ha and Hc are used, and tentracks per field are formed as shown in FIG. 27. FIG. 28 shows thetiming of head switching. While the rotary drum is being rotated at 150rps, the recording current is applied to the magnetic head Ha if thedrum PG pulse goes high and to the magnetic head Hc if the drum PG pulsegoes low.

In the HD mode, all the four magnetic heads Ha, Hb, Hc and Hd shown inFIG. 29 are used, and twenty tracks per field are formed as shown inFIG. 30. FIG. 31 shows the timing of head switching. While the rotarydrum is being rotated at 150 rps, the recording current is applied tothe magnetic heads Ha and Hb if the drum PG pulse goes high and to themagnetic heads Hc and Hd if the drum PG pulse goes low.

FIG. 32 shows a flowchart of mode identification which is executedduring reproduction. First, the current reproduction mode is confirmed(S1). In Step S2, the flow proceeds to any one of Steps S3, S4 and S5 inaccordance with the result of the confirmation which indicates any oneof the SD-Low mode, the SD-High mode and the HD mode. Any value of “5”,“10” and “20” is set in a variable N (S2, S4 or S5).

The mode used during recording is identified on the basis of thesub-code of a reproduced digital signal (S6 and S7), and the subsequentreproduction mode is determined. In Step S7, the flow proceeds to anyone of Steps S8, S9 and S10 in accordance with the determined mode whichis any one of the SD-Low mode, the SD-High mode and the HD mode. Anyvalue of “5”, “10” and “20” is set in a variable M which determines thenumber of tracks per field (S8, S9 or S10).

The variables N and M are compared (S11). If N<M, the running speed ofthe magnetic tape is increased (S12). If N=M, the running speed of themagnetic tape is kept (S13). If N>M, the running speed of the magnetictape is increased (S14). In other words, the running speed of themagnetic tape is controlled to become equal to the tape speed specifiedby a mode selected during recording.

After the completion of Step S12, S13 or S14, the flow returns to StepS1, and the above-described processing is repeated.

An embodiment of a video recording and reproducing apparatus in whichthe down converter shown in FIG. 7 and the up converter shown in FIG. 33are used as broadcasting system converters will be described below withreference to FIG. 34 as well.

FIG. 33 shows one example of an NTSC-HD system converter which serves asthe up converter. In the NTSC-HD system converter shown in FIG. 33, anNTSC signal is decoded through a motion adaptive type NTSC decoder 570,and the aspect ratio of the decoded signal is converted from 4:3 to 16:9in an aspect ratio conversion part 571. Then, the number of scanninglines is converted from 525 to 1,125 in a number-of-scanning-linesconversion part 572, and the field frequency is converted from 59.94 Hzto 60 Hz in a field frequency conversion part 573. Thus, the NTSC signalis converted into an HD signal to be outputted.

FIG. 34 is a block diagram showing a video recording and reproducingapparatus according to another embodiment of the present invention. Anoperator can select recording or reproduction, HD mode or SD mode andthe like on an operation panel 500. The following description refers tofour kinds of operations of the recording and reproducing system of theapparatus. The input signal of this embodiment is an HD signal.

(1) Recording in SD Mode (Long-Time Recording Mode)

“RECORDING” and “SD” are selected on the operation panel 500, and asystem controller 501 connects the movable contact of a switch 506 to acontact {circle around (1)} or {circle around (2)} thereof. An HD inputsignal is down-converted into an SD (for example, NTSC) signal by a downconverter 503. The system controller 501 also controls a switch 502 toconnect the movable contact of the switch 502 to a contact {circlearound (1)} thereof. Thus, the SD signal is recorded on a tape 510through a recording system 509. During this time, an SD monitor 504 isused.

(2) Recording in HD Mode (High Definition Mode)

“RECORDING” and “HD” are selected on the operation panel 500, and thesystem controller 501 connects the movable contact of the switch 502 toa contact {circle around (2)} thereof. The HD input signal is directlyrecorded on the tape 510. During this time, either one of an HD monitor505 and the SD monitor 504 can be selected.

If the HD monitor 505 is to be used, the movable contact of the switch506 is connected to the contact {circle around (1)} or {circle around(2)} thereof so that the HD signal can be directly outputted to the HDmonitor 505.

If the SD monitor 504 is to be used, the movable contact of the switch506 is similarly connected to the contact {circle around (1)} or {circlearound (2)} thereof, and the HD signal is down-converted into an SDsignal by the down converter 503. By connecting the movable contact ofthe switch 507 to any one selected from the contacts {circle around(1)}, {circle around (2)} and {circle around (4)} thereof, the SD signalcan be outputted to the SD monitor 504.

By adopting the above-described arrangement, it is possible to provide acamera-integrated type VTR of reduced size.

(3) Reproduction in SD Mode

“REPRODUCTION” and “SD” are selected on the operation panel 500, and thesystem controller 501 connects the movable contact of the switch 507 toa contact {circle around (3)} thereof. An SD signal reproduced from thetape 510 by a reproducing system 511 is displayed on the SD monitor 504as a reproduced output image. If the SD signal is to be displayed on theHD monitor 505, it is converted into an HD signal by an up converter 508and the movable contact of the switch 506 is connected to a contact{circle around (3)} thereof.

(4) Reproduction in HD Mode

“REPRODUCTION” and “HD” are selected on the operation panel 500, and thesystem controller 501 connects the movable contact of the switch 506 toa contact {circle around (4)} thereof. A reproduced HD signal isdirectly displayed on the HD monitor 505 as a reproduced output image.If the HD signal is to be displayed on the SD monitor 504, the movablecontact of the switch 506 is similarly connected to the contact {circlearound (4)} and the HD signal is converted into an SD signal by the downconverter 503. When the movable contact of the switch 507 is connectedto a contact {circle around (1)} thereof, the SD signal can be displayedon the SD monitor 504. The following table shows the manner ofconnection of the contacts {circle around (1)} to {circle around (4)} ofeach of the switches 502, 506 and 507 during each of the SD and HDmodes.

Recording Reproduction SD

HD

Although in the above-described embodiment the up converter 508 isemployed, a multi-scan monitor may also be used instead of the HDmonitor 505. In the case of the multi-scan monitor, the up converter 508can be omitted because if an SD (for example, NTSC) signal is inputted,the SD signal is scanned by using 525 scanning lines/frame. As theSD-Low mode, an SD signal having a horizontal resolution ofapproximately 230 lines which is a standard image quality in generaldomestic apparatus may also be applied to the multi-scan monitor.

As can be readily understood from the above description, in accordancewith the above-described embodiment, since a compression mode suitablefor image compression processing to be executed in a recording system isselected according to a photographic mode selected in a image pickupsystem, a photographic image can be efficiently compressed by the imagecompression processing, so that good image quality and a highcompression ratio can be achieved.

Further, in accordance with the above-described embodiment, in onecamera-integrated type VTR, it is possible to achieve selectiveutilization of a plurality of camera modes conforming to a plurality ofbroadcasting systems. Also, the setting of a compression mode, such asthe selection of a compression ratio and a compression system for animage, and the setting of the required recording mode in a VTR can beautomatically controlled by a system controller in accordance with theselection of a camera mode. Accordingly, it is possible to realize acamera-integrated type VTR which can be utilized in a variety ofapplications by an easy operation without the need to perform acomplicated connection or operation.

Also, in accordance with the above-described embodiment, since a singledown converter is used to perform recording of a video signal input andreproduction of a recorded video signal, it is possible to reduce thecircuit scale of the apparatus, and it is also possible to selectivelyrecord or reproduce an HD signal and an SD signal. Also, it is possibleto employ an SD monitor as an output monitor for an HD signal input.Further, since the SD monitor can be used as a monitor, it is possibleto realize a camera-integrated type VTR which is reduced in sizecompared to conventional camera-integrated type VTRS.

In the above-described embodiment, the HD mode, the SD-Low mode and theSD-High mode are prepared as the three recording modes. However, thekinds of modes are not limited to these modes, and it is also possibleto use three modes such as HD, SD and ED modes.

The manner of mode identification during reproduction and the sequenceof control to be executed for the mode identification will be describedbelow with reference to FIG. 35.

Step P1: The current reproduction running mode of a VTR is confirmed.

Step P2: A variable N is set to N=10 or N=20 according to which of thethree modes is selected.

Step P3: A sub-code is detected from a reproduced digital signal, andthe mode used during recording is identified on the basis of thesub-code of the reproduced digital signal, and the required reproductionmode is determined.

Step P4: The required number of tracks per unit time M and a datacompression ratio CR are respectively set to M=10 or 20 and CR=5 or 10in accordance with any one of the three modes which is indicated byreproduced ID data.

Step P5: The target value of capstan speed control is set in accordancewith the result of a comparison between the values of the variables Nand M.

The flow proceeds from Step P5 to any one of the succeeding three steps.

If N>M, it is determined that the current speed is greater than thespeed used during recording, and the current speed is decreased.

If N<M, it is determined that the current speed is smaller than thespeed used during recording, and the current speed is increased.

If N=M, the current speed is kept.

Step P6: A data expansion ratio is set to 1/CR and decoding is executed.

The flow returns to Step P1 for confirming the current mode, and theabove-described routine is repeated.

To obtain a better understanding of the operation of the focusingcontrol circuit 61 shown in FIG. 6, the relationship between systemconversion (conversion between television systems) and TVAF (automaticfocusing using a video signal) will be described below with reference toFIGS. 36 and 37.

The amount of information carried by an HDTV signal is approximatelyfive times that of information carried by an existing broadcasting (SD)system. Further, the HDTV signal contains more high-frequency spectrumcomponents than the SD signal.

FIG. 36 shows the level variations of the amount of high-frequencycomponents contained in the respective signals conforming to the twobroadcasting systems with respect to the movement of the focus of animage pickup optical system between its closest-distance position andits infinity position. Both curves A and B reach the respective peaks atan in-focus point.

The curve A indicates the variation curve of the HDTV signal, while thecurve B indicates the variation curve of the existing TV signal. Therelationship between the heights at the in-focus point of the respectivecurves A and B is A≧B.

The relationship between the widths of in-focus areas “a” and “b” inwhich to restart an AF operation is a≦b. A sharper curve provides asmaller in-focus area for which AF restarting computations must beexecuted more frequently. In consequence, the curve A can achieve abetter focusing characteristic in terms of focusing accuracy.

In other words, if HDTV video information which contains a larger amountof information is used, it is possible to achieve TVAF of higherperformance.

For this reason, in an image pickup system employing a down converter,video information which is not yet processed by the down converter issuitably used as information for the aforesaid TVAF.

Incidentally, as shown in FIG. 37, signal frequency components differbetween the existing NTSC and PAL broadcasting systems as well.Accordingly, if optimum ones of the signal frequency components areselectively employed according to the kind of subject or photographicconditions (the illuminance of surroundings), it is possible to improvedetection accuracy.

As shown in the coordinate plane of FIG. 37 which is defined by threekinds of frequency axes, if it is assumed that the horizontalfrequencies of the NTSC and PAL video signals are the same, the NTSCsystem provides a picture which is made up of 60 fields/second withrespect to the temporal frequency axis and 525 scanning lines withrespect to the vertical frequency axis. Accordingly, the video signalcomponents of the NTSC video signal are present in the frequency areadefined by 60/2 and 525/2.

The PAL system provides a picture which is made up of 50 fields/secondwith respect to the temporal frequency axis and 625 scanning lines withrespect to the vertical frequency axis. Accordingly, the video signalcomponents of the PAL video signal are present in the frequency areadefined by 50/2 and 625/2.

By selectively utilizing the different characteristics in accordancewith the kind of subject whose image is to be picked up and the kind ofphotographic mode, it is possible to further improve the performance ofTVAF.

The improvement of the performance of TVAF leads to not only animprovement in the diameter of a circle of least confusion at a finalin-focus position but also an improvement in the stability of theprocess of finding an in-focus position (for example, an unstablebehavior such as hunting or fluctuation can be reduced).

As described above, a subject image is photoelectrically converted bythe CCD built in the HDTV camera 60 and an HD signal having a highdegree of definition and a large amount of information is outputted.

An embodiment in which a concept called “scalability” is applied to thehierarchial structure of image information of a VTR to improve datahandling will be described below with reference to FIGS. 38 to 49.

A technique for performing coding or decoding and recording orreproduction of HD information in a structure in which an NTSC signal isincluded in the HD information will be described below with illustrativereference to a two-layer structure consisting of the HD information andthe NTSC information.

First, encoding of an NTSC signal is performed and the encoded signal istransferred (or recorded).

Then, a non-transmitted or unrecorded information portion is transferred(or recorded).

An operation which is performed by recording means having thearrangement shown in FIG. 38 when an HD signal is inputted thereto willbe described below.

The input HD signal is down-converted into an SD signal by a downconverter 661, and the output of the down converter 661 is inputted toan SD-signal encoder 662. The encoded SD signal is divided into twochannels by a recording channel divider 663, and the two outputs of therecording channel divider 663 are supplied to recording head amplifiers671 and 673, respectively. Then, information recording tracks are formedon a magnetic recording medium 660 by magnetic recording heads 672 and674. In the meantime, the output of the SD-signal encoder 662 issupplied to an SD-signal decoder 665 and, in an up converter 664, theoutput of the SD-signal decoder 665 is converted into an HD signal whichcontains an image distortion (error) occurring during encoding/decoding.If this degradation signal (recording SD information) is subtracted fromthe previous input signal, a difference signal for forming an HD signalcan be obtained. Such a difference signal is formed by a subtractor 669,and the amount of data contained in the difference signal is reduced ina data compressor 666, and the output of the data compressor 666 isinputted into a data formatter 667 for causing the SD signal to conformto the recording standard of the HD signal. The output of the dataformatter 667 is divided into two channels by a recording channeldivider 668 similar to the aforesaid recording channel divider 663. Thethus-obtained HD additional information is supplied to recording headamplifiers 675 and 677. Magnetic recording heads 676 and 678sequentially record and form a pair of HD information recording tracksin an area adjacent to the pair of SD information recording tracksformed by the outputs of the divider 663 on the magnetic recordingmedium 660.

The manner of the above-described recording operation isdiagrammatically shown in FIG. 40.

The SD information and the HD additional information, which are in theinclusive relationship shown by a symbolic block (left) representativeof the amount of image information, are respectively recorded by twopairs of double azimuth (+/−) heads at the rate of two tracks at onetime, and a total of four tracks constitute a basic unit.

The tape transporting speed used during the above-described recordingoperation is selected to be two times the tape transporting speed usedduring SD recording (N=2).

FIG. 39 is a schematic view showing the operation of an SD recordingmode for recording only the SD information on a recording medium by onepair of double azimuth (+/−) heads at the rate of two tracks at onetime.

The tape transporting speed used during this recording operation isselected to be a standard speed (N=1).

An example of the arrangement of reproducing means for reproducingarbitrary information from a magnetic tape on which SD information andHD additional information are recorded in the above-described mannerwill be described below, and the reproducing operation of thereproducing means will be described with reference to FIG. 41.

Signals, which are respectively outputted from a pair of magnetic heads702 and 704 for tracing only a pair of SD information recording trackson a magnetic tape 709 recorded in an HD recording mode, arerespectively amplified by head amplifiers 701 and 703. The signalsoutputted from the head amplifiers 701 and 703 are integrated by a datacombiner 693, and the output of the data combiner 693 is decoded fromits recording data format into an SD signal, such as an NTSC signal, byan SD-signal decoder 692. The SD signal is converted into an HD-signalformat by an up converter 691. The processing of this SD-HD formatconversion is the inverse of the processing performed by theabove-described down converter.

Signals, which are respectively outputted from a pair of magnetic heads706 and 708 for tracing only a pair of HD additional informationrecording tracks on the magnetic tape 709 recorded in the HD recordingmode, are respectively amplified by head amplifiers 705 and 707. Thesignals outputted from the head amplifiers 705 and 707 are integrated bya data combiner 697, and the output of the data combiner 697 is decodedfrom its recording data format into a compressed HD additional signal byan HD-signal decoder 696. The compressed HD additional signal isconverted into an HD additional signal by a data expander 695.

The SD information and the HD additional information which have beenconverted into a common HD signal format in the above-described mannerare added together by an adder 694, whereby the original HD signal isreconstructed.

FIG. 42 schematically shows the manner of the above-describedreproduction from the magnetic tape recorded in the HD recording mode.

Both the period during which a pair of magnetic heads for tracing only apair of HD additional information recording tracks on a magnetic taperecorded in the HD recording mode trace the magnetic tape and the periodduring which a pair of magnetic heads for tracing a pair of SDinformation recording tracks on the magnetic tape trace the magnetictape are selected on the basis of the angle over which the magnetic tapeis wrapped around a head drum. If each of the periods is selected to be180 degrees, an HD additional data reproduction period and an SD datareproduction period appear alternately at intervals of one-half rotationof the head drum.

During each of the data reproduction periods, the signals recorded ontwo tracks are reproduced by either of the pairs of double azimuth headsprovided on the rotary drum. The signals recorded on a total of fourtracks are reproduced as a basic unit.

Accordingly, the signals recorded on four tracks which constitute thebasic unit of the aforesaid information can be reproduced during onerotation of the head drum. The inclusive and combination relationshipsbetween the SD information and the HD additional information which arereproduced in the above-described manner are shown in the right-handpart of FIG. 42 by using symbolic blocks each representative of theamount of image information.

Compatible reproduction which is most important in the present inventionwill be described below.

The following description refers to a case where an SD recordingapparatus having no recording function for the HD recording mode is usedto perform reproduction from a magnetic tape recorded in the HDrecording mode, as shown in FIG. 49.

FIG. 44 shows the manner in which a pair of magnetic heads for tracing apair of SD information recording tracks on a magnetic tape recorded inthe SD recording mode traces the magnetic tape to reproduce an SDsignal. Only one pair of double azimuth heads are provided on a headdrum, and SD information alone is recorded on each track of the magnetictape. In this case, each SD data reproduction period occurs only onceduring one rotation of the head drum. Since the tape transporting speedis the standard speed (N=1), the SD information recorded on eachrecording track is sequentially reproduced without skipping any of therecording tracks. FIG. 44 schematically shows the manner of theabove-described reproducing operation.

If recording-mode identification information, such as ID, is detectedfrom a video area or a sub-code area by the detector 771 shown in FIG.49 during the SD recording mode reproducing operation, a compatiblereproduction mode is selected. When a servo circuit 773 receives aninstruction from the detector 771, the servo circuit 773 sets thecurrent tape transporting speed to a double speed equal to the tapetransporting speed for the HD reproduction mode. Incidentally, a motor774 is provided for driving a capstan, and a frequency generator (FG)775 is provided so that the servo circuit 773 can confirm the state ofrotation of the capstan.

The pair of double azimuth heads for SD signals, which are provided onthe head drum, trace only pairs of SD information recording tracks on amagnetic tape recorded in the HD recording mode. However, since nomagnetic heads for HD signals are provided, the magnetic tape istransported without tracing a pair of HD additional information tracks.Accordingly, an HD addition data track idle running period and an SDdata reproduction period alternately appear at intervals of one-halfrotation of the head drum. FIG. 43 schematically shows the manner of theabove-described reproducing operation.

Reproduction from only two tracks for SD signals out of four trackswhich constitute one basic unit is performed by the pair of doubleazimuth (+/−) heads provided on the rotary drum, at intervals of onerotation period.

The signal reproduced in the above-described manner is converted into anSD signal, such as an NTSC or PAL signal, by the SD-signal decoder 772shown in FIG. 49, and the SD signal is outputted from the SD-signaldecoder 772. The manner of the above-described reproduction from therecorded tracks is shown in FIG. 45 in the form of a recording trackpattern.

The recording tracks shown in FIG. 45 constitute groups each consistingof four tracks indicated by characters “a” to “d” affixed to therespective numbers.

The characters “a” and “b” indicate tracks for SD signals (representedby meshes), and the characters “c” and “d” indicate additional tracksfor HD signals.

In the compatible reproduction mode, reproduction from only the tracks“a” and “b” is performed, and no reproduction from the track “c” nor “d”is performed.

FIG. 46 is a graphic representation showing a head relative speed Vheaddetermined by a tape transporting speed Vtape and a head drum rotationalspeed Vdrum, and the horizontal and vertical axes represent the tapetransporting speed Vtape and the head drum rotational speed Vdrum,respectively.

Since the head relative speed Vhead reaches 9,000 rotations during theSD mode, it is not practical to increase the rotational speed to afurther extent for the purpose of coping with the HD mode. If therotational speed is selected to be not less than 9,000 rotations, twokinds of trace angles are formed in the case of the respective standardand double speeds, as shown in FIG. 46.

A line V1 indicates the case of reproduction of an SD mode recording,and a line V2 indicates the case of reproduction of an HD moderecording. In the case of the compatible reproduction mode according tothe present embodiment, the tape transporting speed Vtape and the drumrotation speed Vhead are completely the same as those used in the HDreproduction mode, the head trace V2 is selected so that an SD trackportion can be traced without any problem. Each of FIGS. 47 and 48 is atable showing whether each of the SD and HD reproduction modes can beused for magnetic tapes recorded in the respective SD and HD recordingmodes, and FIG. 47 shows the case of an SD signal reproducing apparatus,while FIG. 48 shows the case of an HD signal reproducing apparatus.

As can be seen from FIGS. 47 and 48, not only the HD signal reproducingapparatus but also the SD signal reproducing apparatus can effectreproduction from any of the magnetic tapes recorded in the SD recordingmode or the HD recording mode.

It is to be noted that since reproduction from a magnetic tape recordedin the SD recording mode can be performed in the HD-signal format,“recording mode SD/reproduction mode HD” of FIG. 48 can also be regardedas “possible” although the image quality, such as resolution, isequivalent to SD quality.

In the present embodiment, although the concept of a hierarchical codingsystem has been described with illustrative reference to pyramidalcoding, the kind of coding system is not limited to the pyramidalcoding. For example, another hierarchical coding technique, such assub-band coding, can of course be used without departing from the scopeand spirit of the present invention.

Incidentally, the head relative speed Vhead is not limited to 9,000rotations, and, for example, 4,500 rotations may be selected. It is alsopossible to adopt an arrangement which switches the head relative speedVhead as well as the characteristics of its control system on the basisof a decision as to whether the HD mode or the SD mode is selected.

According to the embodiment utilizing the above-described scalability,it is possible to achieve a remarkable improvement in the characteristicof compatible reproduction from a recorded medium, which cannot beattained by conventional image recording systems because of theirdifferent coding systems.

Also, it is possible to effect reproduction from a recording mediumrecorded in any recording mode, by means of not only higher-orderequipment but also lower-order equipment.

Furthermore, since a lower-order system needs only to have a servomechanism for effecting switching between media driving speeds, userscan easily introduce lower-order systems without making large priorinvestments.

1. A method of an image process, comprising the steps of: a) designatingan image size selected from a plurality of image sizes and a compressionmode selected from a plurality of compression modes respectively; b)resizing an image signal in accordance with designation by saiddesignating step; c) compressing said resized image signal in acombination of a DCT, a quantization and a coding process in accordancewith designation by said designating step; d) adding additional datacorresponding to said image size and said compression mode designated bysaid designating step to the compressed image signal; e) recording saidcompressed image signal and said added data added by said adding step ona recording medium; f) reproducing said compressed image signal recordedby said recording step; g) detecting said added data recorded by saidrecording step; h) converting image resolution of said reproduced imagesignal in accordance with said added data; and i) displaying said imagesignal converted by said converting step.
 2. The image process methodaccording to claim 1, wherein in the step of resizing the image signalincludes a down convert process.
 3. The image process method accordingto claim 1, wherein in the step of converting image resolution includesa down convert process or an up convert process.
 4. The image processmethod according to claim 1, wherein said recording medium includes atape.
 5. The image process method according to claim 1, furthercomprising the step of adding error correction code to the compressedimage signal.
 6. The image process method according to claim 1, whereinsaid compression mode includes a compression ratio.
 7. The image processmethod according to claim 1, wherein said additional data includesdiscrimination data indicative of an HD standard or an SD standard. 8.The image process method according to claim 1, wherein said additionaldata includes discrimination data indicative of compression ratio.
 9. Amethod of a movie image process, comprising the steps of: a) designatingan image size selected from a plurality of image sizes and a compressionmode selected from a plurality of compression modes respectively; b)resizing a movie image signal in accordance with designation by saiddesignating step; c) compressing said resized image signal in acombination of a DCT, a quantization and a coding process in accordancewith designation by said designating step; d) adding additional datacorresponding to said image size and said compression mode designated bysaid designating step to the compressed movie image signal; e) recordingsaid compressed movie image signal and said added data added by saidadding step on a recording medium; f) reproducing said compressed movieimage signal recorded by said recording step; g) detecting said addeddata recorded by said recording step; h) converting image resolution ofsaid reproduced movie image signal in accordance with said added data;and i) displaying said movie image signal converted by said convertingstep.
 10. The image process method according to claim 9, wherein saidcompression mode is set to a predetermined bitrate.
 11. The imageprocess method according to claim 9, wherein in the step of resizing theimage signal includes a down convert process.
 12. The image processmethod according to claim 9, wherein in the step of converting the imageresolution includes a down convert process or an up convert process. 13.The image process method according to claim 9, wherein said recordingmedium includes a tape.
 14. The image process method according to claim9, further comprising the step of adding an error correction code to thecompressed movie image signal.
 15. The image process method according toclaim 9, wherein said compression mode includes a compression ratio. 16.The image process method according to claim 9, wherein said additionaldata includes discrimination data indicative of an HD standard or an SDstandard.
 17. The image process method according to claim 9, whereinsaid additional data includes discrimination data indicative ofcompression ratio.
 18. The image process apparatus, comprising: a)designation unit, adapted to designate an image size selected from aplurality of image sizes and a compression mode selected from aplurality of compression modes respectively; b) resize unit, adapted toresize an image signal in accordance with designation by saiddesignation unit; c) compression unit, adapted to compress said resizedimage signal in a combination of a DCT, a quantization and a codingprocess in accordance with designation by said designation unit; d)adding unit, adapted to add additional data corresponding to said imagesize and said compression mode designated by said designation unit tothe compressed image signal; e) recording unit, adapted to record saidcompressed image signal and said added data added by said adding unit ona recording medium; f) reproducing unit, adapted to reproduce saidcompressed image signal recorded by said recording unit; g) detectingunit, adapted to detect said added data recorded by said recording unit;h) converting unit, adapted to convert image resolution of saidreproduced image signal in accordance with said added data; and i)display unit, adapted to display said image signal converted by saidconverting unit.
 19. The image process apparatus according to claim 18,wherein said resize unit includes a down converter.
 20. The imageprocess apparatus according to claim 18, wherein said converting unitincludes a down converter or an up converter.
 21. The image processapparatus according to claim 18, wherein said recording medium includesa tape.
 22. The image process apparatus according to claim 18, furthercomprising an ECC unit, adapted to add an error correction code to thecompressed image signal.
 23. The image process apparatus according toclaim 18, wherein said compression mode includes a compression ratio.24. The image process apparatus according to claim 18, wherein saidadditional data includes discrimination data indicative of an HDstandard or an SD standard.
 25. The image process apparatus according toclaim 18, wherein said additional data includes discrimination dataindicative of compression ratio.